Abb Research Ltd.

Ralf-Dieter Pietsch

Bernhard Deck

Lutz Niemeyer

Klaus-Dieter Weltmann

Michael Stanimirov

Walter Rueegg

Current and voltage values (uk, ik) are measured for protection of an electrical power line ( ). An adaptive estimator is used to analyze all the values within a measurement window, and to convert them to impedance values (Z). The line ( ) is switched off if the impedance values (Z) assume unacceptable values. In order to shorten the reaction time, a warning signal (W) is produced if powerful radio-frequency signals are detected on the line ( ). When the warning signal (W) occurs, the respective measurement window is located such that its start matches the time of the warning signal (W), and/or the respective measurement window is shortened.

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Oberlichtenau, Germany

Ralf-Dieter Pietsch